UK Met forecasts above normal Atlantic hurricane activity in 2023

A 2023 Atlantic hurricane season forecast from the UK Met Office is calling for a high level of tropical storm activity this year, with an above normal number of hurricanes and major hurricanes expected to form, the first of the forecasters we track to suggest a more active season is coming.

The rest of the hurricane season forecasts we track here at Artemis had opted for below-average to about average levels of activity, citing an expectation that the development of an El Niño will quench storm activity in the tropics.

But, as we’ve reported before, some meteorologists are saying that warmer than normal sea surface temperatures (SST’s) in the Atlantic tropics introduce a lot of uncertainty and the UK Met Office appears to be opting for this warm SST dynamic and also lower than normal wind shear to accentuate storm activity throughout this 2023 hurricane season.

The UK Met Office forecasts 20 named tropical storms will form this season (with a 70% chance that the number will be in the range 14 to 26), 11 of which becoming hurricanes (with a 70% chance that the number will be in the range 8 to 14), and 5 intensifying to major hurricane status (with a 70% chance that the number will be in the range 3 to 7).

That’s a forecast some way above the long-term average of 14 named storms, 7 hurricanes and 3 major hurricanes.

In addition and underscoring the high number of tropical storms forecast for the 2023 Atlantic hurricane season, the UK Met Office also calls for an accumulated cyclone energy (ACE) index of 222, way above the 121 long-term average.

The UK Met Office believes that while there is “a strong signal in our forecasts for El Niño to develop and persist through the peak of the Atlantic hurricane season (August to October 2023,” it may not suppress storm activity as other forecasters have predicted.

“This would normally be expected to increase vertical wind shear across the tropical North Atlantic, suppressing tropical storm activity,” they explain, but say that their forecast number “predicts most likely high tropical storm activity in the Atlantic.”

Two factors lead them to this conclusion.

“Vertical wind shear through the troposphere over the tropical Atlantic is predicted to be lower than previously seen during El Niño events,” and “Sea surface temperatures are predicted to remain well above average across the tropical North Atlantic during the whole hurricane season,” they explained.

“Current El Niño forecasts suggest that the transition from neutral to El Niño conditions is likely to take place over the next few months. However, the speed of transition, its intensity and the time it takes to influence Atlantic hurricane activity will all have a direct bearing on the season ahead with the upper end of the Met Office forecast providing a reasonable worst-case scenario,” the UK forecaster concluded.

Including the UK Met Office forecast to our other 2023 Atlantic hurricane season forecasts that we track gives an updated Artemis average for 14 named storms, 7 hurricanes and 3 major hurricanes.

Track the 2023 Atlantic tropical storm and hurricane season on our dedicated page and we’ll update you as new information emerges.